Since the early 1980s, adjustable gastric bands have provided an effective alternative to gastric bypass and other irreversible surgical weight loss treatments for the morbidly obese. The gastric band is wrapped around an upper portion of the patient's stomach, forming a stoma that restricts food passing from an upper portion to a lower portion of the stomach. When the stoma is of the appropriate size, food held in the upper portion of the stomach provides a feeling of fullness that discourages overeating. However, initial maladjustment or a change in the stomach over time may lead to a stoma of an inappropriate size, warranting an adjustment of the gastric band. Otherwise, the patient may suffer vomiting attacks and discomfort when the stoma is too small to reasonably pass food. At the other extreme, the stoma may be too large and thus fail to slow food moving from the upper portion of the stomach, defeating the purpose altogether for the gastric band.
An implantable band may be utilized in any number of applications within a patient's body where it is desirable to establish and/or vary the size of an orifice or organ. As used herein and in the claims, an implantable band is a band which may be implanted in a position to vary the size of an organ, or an orifice or an anatomical passageway, such as a stomach or lumen.
Depending upon the application, some prior art bands take the form of a flexible, substantially non-extensible band containing an expandable section that is capable of retaining fluids. The expandable section, such as a hollow elastomeric balloon, is typically capable of expanding or contracting, depending upon the volume of fluid contained therein.
Bidirectional flow control is required to increase and decrease the size of the stoma created by the band. Adding or removing saline solution to effect a change in size of the stoma created by an implantable band may be accomplished by us of an implanted bidirectional flow device, such as for example a subcutaneously implanted fluid injection port or bidirectional infuser pump, such as disclosed in U.S. patent application Ser. No. 10/857,315, filed on May 28, 2004, for Thermodynamically Driven Reversible Infuser Pump For Use As A Remotely Controlled Gastric Band, U.S. patent application Ser. No. 10/857,762, filed on May 28, 2004, for Piezo Electrically Driven Bellows Infuser For Hydraulically Controlling An Adjustable Gastric Band, U.S. patent application Ser. No. 10/857,763, filed on May 28, 2004, for Bi-Directional Infuse Pump With Volume Braking For Hydraulically Controlling An Adjustable Gastric Band, and U.S. patent application Ser. No. 10/856,971, filed on May 28, 2004, for Metal Bellows Position Feedback For Hydraulic Control Of An Adjustable Gastric Band, all of which are incorporated herein by reference.
Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings.